A View from the Inside of BP: “Hubris” Before the Blowout

Yesterday, I received an account from someone who I believe is very close to the events leading up to the blowout of BP’s Mississippi Canyon Block 252 well. This account provides a very detailed, technically correct, yet chilling description of the conditions surrounding this well from drilling through cementing, up to the operations they were undertaking when the well got away from them. Like other accounts I’ve heard, this one leaves questions about key details that only BP and Transocean can answer, if they’ll break their silence about these critical pieces of information only they can provide.

This account begins with a general statement about well conditions when drilling, describing problems very common with big wells. Because of these drilling problems, as well as the well logs they had run, BP knew they had a big discovery. Before I go on with this story, I need to give a little background to those readers not familiar with the oil and gas industry.

Wells capable of big production generally have very high porosity (or pore space in the reservoir rock) that holds oil, gas, and water. It’s important to understand that oil does not sit in caverns underground as is commonly believed. Oil and gas actually reside in the space between sand grains in sandstone; as an analogy, think of the way a sponge holds water. When you encounter high porosity and high permeability (the ability of fluids to flow within the rock) you’ve got potential for big production as long as pressure and, of course, the hydrocarbons themselves are present. In this well, BP had all of these characteristics. In spades.

These high porosity zones, and often sections above them, can be very difficult to drill. These wells are drilled with a weighted drilling mud, designed to keep enough hydrostatic pressure in the hole to keep well pressure back. There is a fine balance, though. Too much mud weight, and the well will start taking fluid, reducing hydrostatic head, then kick when reservoir pressure overcomes the column weight. Too little mud weight, and the well will kick straightway. These are exactly the conditions described in this account. This well required 16 lbs per gallon weight, which likely translates to bottom hole pressure somewhere around 15,000 lbs per square inch (PSI) at 18,000 feet (5,000 feet above the sea floor, 13,000 feet below it). That’s big.

As I’ve talked about before, based, on other accounts, BP ran production casing and cemented with nitrified cement to make a lightweight slurry to keep the well from losing circulation. Remember, the top of the well is at 5,000 below sea level, so it is reached from the surface with drill pipe through the riser. Once the pipe is hung off with a casing hanger and cemented, weight is then set down to seal a “packoff” in the hanger assembly that sits in the casing head. The purpose of this packoff is to seal between the production casing and the surrounding string of pipe. This particular description all squares with other accounts I’ve received. This account describes the setting of the assembly and the successful test to 10,000 PSI pressure.

Here’s where this account varies from others I’ve heard. Apparently, after hanging off the casing, cementing, setting the packoff, and testing, they came out of the hole with drillpipe, then went back with a bridge plug to set in the top of the casing to seal the inside. A bridge plug is a mechanical device, in this case run on drillpipe, that is set with weight from the drill string after it is turned to activate it. With two plugs in the casing, and the packoff outside the casing, the well should have been safe.

The writer of this account is unsure whether the bridge plug was actually set before the rig crew displaced the mud in the riser with seawater. It makes sense to me that it would be, and that they had pulled up into the BOP to displace the mud so the riser and the BOP stack would be clear of mud when they separated to recover the riser. An earlier account said that they had closed the annular preventer at this point, but this description does not include that particular step. Instead, the account writer believes that the casing hanger packoff failed as the hydrostatic weight of the mud was reduced while being replaced with the lighter seawater. If this is true, then there was a catastrophic failure of the hanger packoff, likely because the backside pressure exceeded the rated ability of the assembly to hold. This explains the sudden pressure at the surface and makes more sense than an experienced operator opening a BOP with pressure on it as was told from an earlier account. This description clearly supports a backside blowout around the outside of the production casing.

This next part of the narrative is graphic, describing the tragic and sudden failure of all systems on the rig, but doesn’t explain the failure of the BOP deadman to activate the shear rams in the stack. It was a calm night, so when gas hit surface, it settled, being heavier than air, around the rig floor, even as the blowout strengthened. The air inductions for the deck engines that run the rig are nearby on the floor, so when they breathed in the gas/air mix, the engines ran away with themselves uncontrollably and exploded, lighting off the cloud of gas and the flow from the well. Similar explosions happened in the mud pump room, destroying inner walls, which, according to this account, were unfortunately adjacent to the living quarters. In a strange twist of fate, the off-shift crew was reportedly having a party in the living quarters, celebrating 7 years of accident free performance. Dear God. This writer confirms that there were 7 BP bigwigs visiting on the rig at the time, which we’ve now heard from several sources.

11 crew were killed; 9 on the drilling rig floor, and 2 mud engineers in the mud room. It’s a miracle that the rest got off, including apparently, the BP executives. This writer’s most compelling statement?

“We never have had an accident like this before, so hubris, the folie d’grandeur, sort of takes over. “

Hubris. Illusions of grandeur. I believe that the Deepwater Masters of the Universe had been so successful lucky that they were over-confident. Having never experienced this kind of failure, it was inconceivable to them that it could happen. It did. They turned their backs on this beast, and it attacked.

With a deadly, disastrous vengeance.

I continue to call on BP and Transocean to publicly disclose their operations that night and to answer the questions that are being asked. Only then do we know what steps we can take to prevent this from ever happening again. This account may not be 100% accurate, but squares with enough of key the facts in other accounts I’ve heard that I have no reason to believe it’s not genuine. I’ll continue to chase this story.

Comments

As disasterous as this is. I think us laymen would be interested in knowing how many offshore drilling rigs, worldwide we have in operaton at any one time? MY recollection of major oil rig fires includes only two previous to this, that one in the South Pacific, Global Marine I think, and the Mexican well in the Bay of Campeche that dirtied up Texas beaches some 20+ years ago. Can you fill us in? I’ve heard there are some 2,500 offshore drilling rigs worldwide. If so, that really is a pretty good safety record, overall. Just curious.

They set a bridge plug deep in the 7″ production csg. They picked up to 3000 ft below ML. Displaced to SW to pump a balanced plug at 3000 ft.
Collapse pressure on 125 ksi 9 7/8″ prod csg is +/- 11,125 psi. If pore press at 7″ shoe is +/- 14.2 ppg, and they have 8.6 SW to 3000 ft BML, you already have at least 2300 psi collapse due to differential on backside of 9 7/8″.
If you have gas migration to wellhead, at that point you only need 8800 psi to collapse the 9 7/8. Coincidentally, the burst on 125 ksi 16″ 109# parent casing is about 8900 psi!
The 9 7/8″ csg hanger seal at wellhead might have broke down, but that thing is a serious hunk of iron. I’d bet either the 9 7/8″ collapsed and it flowed inside the csg hanger around the DP and up the riser.
Side note they used H-523 on the 9 7/8″. They had started internal study reviewing those connections for seal integrity issues.
Scary thing is, if they had gas migration behind the production csg, this probably would have happened even without displacing to SW. Swellable elastomers just got the biggest endorsement ever.
Wombat, yes, they will come clean. No question. Too many vendors are required in these projects to hide anything. It really is a team effort in this area of the industry, when a bad thing happens all the vendors feel it, not just the ones who are directly pinched. On a $1.8 billion project, there are 10s of 1000s of people who touch this single project alone. Besides, I am pretty sure Anadarko will want to know what the hell happened.
Carguy, for info on all offshore rigs, go to rigzone.com, click “rig data”

I came across the same account last night in the comment thread over at theoildrum.com. Submitted by one called, “mad dog”, you find the entry 1/3 the way down the thread. (www.theoildrum.com/node/6430).
I read it, and about halfway through, I began to think I was reading a PR story. I mean no disrespect to anyone, or their friends, it’s just that the voice and writing style, let alone the ability to paint a complete picture, and the ability for the message to spread so quickly, and be accepted so readily., well, I guess it just feels too neatly crafted. This is a catastrophic event and painting one team as the main cause without factual evidence is too easy to accept.
And so I would like to see some names and people come forward too. And if BP and Transocean don’t come forward, then people will result to anonymous sources that may or may not have been on the rig, and may or may not have their facts 100%, and that may or may not have heard things third person. Perhaps the author of this particular summary of events would also step forward too.
The narrative does feed the hunger to know more, and potentially our biases too…but at what expense?
Rob

Can you comment on the likelihood of drilling a relief well being unsuccessful? I saw an interview where the speaker was doubtful that drilling a relief well would be successful because of the precision required to hit a seven inch pipe at that depth.

The well, while not a slam dunk, is doable. The industry has been steering wells to specific targets for years. The problem is not so much finding the well as much as getting into it once they do. They will need to get into the same well bore in order to pump heavy mud or cement into it. Risk of blowout of the relief well is real.

Your pressures may be a bit off. To calculate Hydrostatic pressure the formula is:
.0512 x True vertical depth x Mud weight in pounds
Since this is exploration I will assume they drilled vertical.
0.0512 x 18000 x 16 = 14745 psi.
Early reports were that they had just finished pumping a ‘balanced cement plug’. This means that the hydrostatic of the cement was meant to equal 14745 psi. If they pumped a light cement of only one tenth of a pound they would have been under balance by:
0.0512 x 18000 x 0.1 = 100 psi.
This does not sound like much but 100 pounds per square inch of pressure can kill if on a line at the surface.